* configure.ac, modules/codec/Modules.am, modules/codec/speex.c: new speex decoder and packetizer using libspeex.
* modules/demux/ogg.c: added support for speex to the Ogg demuxer.
* modules/mux/ogg.c: added support for speex to the Ogg muxer.
* src/misc/variables.c: when creating choices object variables with inheritance enabled, automatically add the inherited value to the list of choices.
* modules/access/udp.c: use an object variable and inheritance for "udp-caching".
* src/input/input.c: disable the hack for filenames with colons on win32 because filenames can't contain colons.